The objective of the present investigation is to document the strength of the relationship between growth in weight and height in the first year of life and the following variables throughout adolescence: weight, height, blood pressure, skinfold thickness, bone age, stage of sexual development, and a series of socioeconomic and family variables. The sample of approximately 700 boys and girls is drawn from the heaviest and the lightest infants, based on expected weight for observed length at the one year examination, within a population of approximately 5000 infants. The objective of the present supplemental grant request is to explore the relationship between serum cholesterol, and adolescent growth within a subsample of this group. To the extent possible all children in the sample will have their serum cholesterol recorded during their second visit. This study will help to elucidate the interrelationships between infant growth, growth in adolescence, and serum lipid levels in adolescence.